You can purchase kits online to run your generator on propane, but I believe that if an engine is not specifically designed to run on propane it can be ruined. I think the propane causes the engine to burn hotter. I inquired about this specifically from Generac and that’s what they told me.
The manufacturer of anything will always tell you that if they don’t supply (and profit from) the kits.
The conversions actually have a great record. Correct jetting is required and supplied.
and others.